The Department of Energy warns in a new report that the aging electric grid, which provides most electricity to the nation, faces threats from terrorism and storms caused by climate change that could knock out Wall Street, hospitals and the Internet if left unfixed.

In the administration's first-ever "Quadrennial Energy Review," the department suggests that modernization is a must and estimated the cost at updating just the grid of transmission and distribution lines at $900 billion. Add in updating power plants, and the price reaches $2 trillion.

The department has been warning of an "aging, inefficient, congested" electric grid for a decade. In recent years, fears of terrorism, climate change storms and even solar flares have added to the list of concerns and prompted a national debate on protecting or modernizing the grid.

In the new report, the Energy Department warns that modern life could be endangered if the grid went down. A congressional report has warned that a solar flare or terrorist attack could darken the grid for a year, during which most of those supplied by grid would die.

"Modernization of the grid has been made all the more urgent by the increasing and now virtually pervasive dependence of modern life on a reliable supply of electricity," said the just-issued Energy Department report.